High-level client API

Design and implement a high level library (HLAPI) based on tox4j targeting the JVM.
The idea here is to create a layer of logic between the low level API and the
concrete client implementation. It should handle all the aspects of Tox that a
client should support, including buddy lists, user informations, file transfers and chat logs.
It should be platform-independent (no direct file I/O, for instance), run on the JVM
and be easily useable from Java.